Galvanometer.



PATENTED FEB. 20, 1906.

P. H. WYNNB.

GALVANOMETER.

APPLICATION FILED JULY 14, 1905.

3 SHEETS-SHEET 1.

PATENTED FEB. 20,1906.

P. H. WYNNE. GALVANOMETER.

APPLICATION FILED JULY 14,1905.

a SHEETS-SHEET 2.

if law No. 813,269. PATENTED FEB. 20, 1906. P. H. WYN'NE. GALVANOMBTER.

APPLICATION FILED JULY 14, 1905.

' 3 SHEETS-SHEET 3.

Fave/M4 27? /azvpizig me,

whit/sy PlllLlP HENRY l/VYNNE. F BOSTQN, lllASSACHUSETlTb, ASSTGDIGR, BY )lltlfitl'l AND MESNE ASSIGNMENTS, (ll @NlG-HALF TU AGNES SETTS.

l WYNNE AND ONEHALF L. E. KNUTT APPARATUS COit'lPANY, F BOSTQN, ll/TASSACHUSETTS, A CQRPUEATTUN 0F MAtlSAUllU- no. erases.

fipecification of Letters Patent.

Patented Feb. 2Q, 1906.

Application filed ly 14,1905. Serial No. 269,640.

To all whom, it may concern:

Be it known that l, PHILIP HENRY -W YNNE, a citizen of the United States,residing at B0ston, in the county of Suffolk and State of lllnssachusetts, have invented an Improvement in Galvanometers, of which the following description, in connection with the accompanying drawings, is a specification, like numerals on the drawings representing-like parts.

This invention relates to a galvanometer, and has for its object to provide an instrument of this type which is simple and inexpensive to manufacture and which is accu rate in its operation.

The features wherein the invention resides will be more fully hereinafter described and then pointed out in the claims.

Figure is a side view of my improved galvanometer. is a top plan view. 2% is a view of the plate carrying the scale. i a is a similar view'of the plate carrying the fiducial inarln Fig/5 is a view showing the frame carrying the scale and fiducial mark removed and iolded. Fig. l"; is a section on the line in at, l, looking to the right. Fig. 7 is a bottom plan view of the base.v Fig. 8 is a section on the line y y, l ig. Fig. 9 1S 3 u v C a detail of the lastemng device for the frame.

carrying the scale. Fig. 10 is a perspective view of the magnet. Fig. i]. is a section on line (i d, Fig. c. Fig. 12 is a vertical section through the coil... Fig. 13 is a detail of the post to which the suspending cord is secured. Fig. 14- is a detail of one of the levelin screws; and Fig. 15 is a section on line b l i p; n

l he principalfeatures or any galvanometer of the type known as DArsonvalf are a magnet, a coil stipported in the field of the magnet, and some form of reading device by which the deflection of the coil can be de nined. lly present invention relates to gal' mometers of this class, has for its object to simplify their co truction and to Mister fl is compact and ported by a suitable base 5. Said distancepiece is herein shown as a pair of stilts or struts 4. The pole-pieces of the magnet 3 are designated by 6. They extend parallel to each other, and between them issupported the usual coil 7 the construction of which will be more fully described hereinafter. The magnet is held in its vertical position by means of supports 9, preferably of channel shape, which rise from the base 5 and are secured thereto by angle-shaped foot-pieces 8. The channel-shaped supports 9 embrace the edges of the magnet 3 and are secured thereto by bolts 71 and are confined at their lower ends between the angle-iron 8 and the stilts i. In order to protect the delicate parts of an instrument of this class that is, the coil, its suspending devices, and the mirror, etc-from disturbing factors, such as wind-currents, dust, &c., it is customary to inclose the magnet and the coils within a case having a. glass window. ln my present invention protection of the delicate parts is accomplished by placing two pieces of glass 10 on opposite sides of the magnet, so that said glass, the magnet, and the stilts 4 themselves form the inclosure within which the coil is suspended. -The use of glass the front and back of the magnet permits the observer in reading the instrument to see the fidueial mark and the scale reflection in the mirror, as will be presently described, and by supporting the lass front and back 10 by, the magnet the evice is made much more compact than galvanometers as commonly constructed. Moreover, with this construction the entire interior of the magnet is illuminated and the operation of the instrument is very easily observed. .[iLS herein shown, the glass is confined between the inturncd edges 1 l of the supports 9 and the magnet, and said glass may be readily removed by sliding it upwardly in the runway formed by said inturned edges ll. of this simple construction the working parts of the instrument are made readily accessible and yet are perfectly protected and thoroughly lluminot +1" or special con i tion, .0

l op er. 'The upper end 14 of this casing is pre erably cone-shaped and has secured thereto the supporting-Wires 15, which are twisted togetherat their lower ends and are opened at their upper ends to form the suspending-loop 16. Secured to said loop 16 is the metallic suspension-ribbon 17, which 1s fastened at its upper end to a suspension-rod 18, which extends through the top of the magnet 3. The lower end of said suspension-rod is cut away, as at 19, (see Fi 13,) to

' form a surface substantially in t e axial from turning and also from Vertical move-' ment by a clamping-screw 22, operating in a i collar 23, fast with said sleeve. Above the collar 23 is another collar 24, through which the suspension-rod 18 passes, said collar carrying a clamping-screw 25. When the clamping-screw 22 is loosened and the clampingscrew 25 is tightened, the suspension-rod may be freely turned bymeans of a suitable handle 26-, said rod being held from downward movement by the collar 23.

One end of the coil 12 may be fastened either directly to the supporting-wires 15 or to the metallic shell 13, and the wire from the other end is taken through a block 31 of nonconducting material and is connected. by means of a non-directive spiral 28 of ,fine metallic ribbon and a wire 29, with the binder-- post 30 in the base 5. The shell 13 surroundinn the coil is Very effective in clamping the vi rations of the coil when the instrument is in use. The block 31 may be of wood or any other suitable non-conducting material. It.

. is preferably conical in sha e and forms the lower conical end or head 0 the shell 13.

32 designates a mirror which is secured to the loop 16 in any suitable way, said mirror bemg so placed thatthe loop projects'above the mirror, thus leaving an open space directly above the mirror, through w ich the fiducial mark can be observed.

The construction of the scale and fiducial mark by which the movement of the coil is notedand the manner of reading it are substantially the same as in the apparatus shown in my Patent No. 763,829, dated June 28, 1904.

35 designates a plate or card bearing a properly-graduated scale 36. in practice I- prefer to make said plate or card with the sight-opening 37, directly beneath which the graduations are placed. The fiducial mark 38 is carried by another card or plate 39. The plates 35 and 39 are located on opposite sides of the 'galvanometer, as seen in Fig. 1, the side of the plate 35 carrying the scale clamping member is and the side of the plate carrying the mark 38, both being faced toward the gal-- vanometer. The reflecting surface of the mirror 16 faces the scale 36 and is midway between the scale and fiducial mark, and when the parts are properly adjusted the observer looks through the sight-opening 37 and sees in the mirror. the reflection of the scale 36 and also sees the fiducial mark 38.

p The instrument is read by noting the relative movement of the scale and fiducial mark. For a fuller description of the method of using the instrument referenhe is had to the aboveable brackets 43 in such a way that they can be adjusted longitudinally and also turned about a vertical axis. As herein shown, each bracket 43 is provided with the horizontal portion 45, having an aperture through which extends a clamping member 46. Each rovided with themclined slot 47, in whic one of the rods40 is received, and the upper end of said clamping member is screw-threaded into a clampingnut 48. Nhen the clampin nuts 48 are tightened, the rods 40 are rawn tightly against the brackets, and thus clamped in their adjusted position. When theclam ingnuts are loosened, the rods 40 may be adjusted lon itudinally to bring both the scale and the fi ucial mark the proper distance from the mirror and also may be turned laterally, as shown in dotted lines, Fig. 2. It will be observed that during the lateral swinging movement of the rods 40 they have what is commonly known as the parallel-ruler motion, and therefore so long as theserods have only a lateral turning movement the lates 39 and 35 will be maintained in paralle ism. In adjusting the instrument preparatory to makinga test with it it is desirable that the mirror, fiducial mark, and scale be so ad-,

justed with relation to each other that to the observer, looking through the sight-opening 37, the reflection in the mirror of the zeromark on the scale will be in alinement with the fiducial mark 38. In mostgalvanometers this adjusting mustbe done by turning the coil and the mirror, an operation which must be performedvery delicately and with great. care. With my improved parallelruler construction the o erator can properly adjust the instrument y simply swinging the rods 40 laterally, as shown in dotted lines,

erases Fig. 2, until the fiducialmark andreflection of the scale in the mirror have the proper relation to each other. This adjustment, of course, can also be made in the other manner, if desired, by turning the suspension-rod 18, and thereby turning the mirror; but the simpler and easier way is to make the adjustment byswinging therods 40. Fig. 5 illustrates how the rods and the plates 39 and 35 can be folded together when the instrument is packed for transportation.

When the instrument is notin use or when it is being transported, it is essential that the weight of the coil 7 betaken from the extremely delicate suspension-ribbon 17 and that said coil be tightly clamped to prevent its having any movement. I have provided for this as follows: designates a U-shaped plate of sheet material which is placed be tween the legs of the magnet and rests on the pole-pieces 5 thereof, said plate being held in' position by the bolts 71. The horizontal portion of said plate has the aperture 51 therethrougb. through which the supportingwires 15 pass freely, said aperture having a slot 52 leading thereto to permit the parts to be assembled. 53 designates a clamping lever which is pivoted either to one of the stilts 4 or to one of the angle-pieces 8. Both ends of said lever are forked, the forked end 54 straddling the wire leading from the coil and being constructed to engage the head 31 and the other forked end 55 straddling the clamping-screw 56, which is provided with two enlargements or collars 57 either side of the clampinglever. Theclamping-nut 55 works in a fixed nut 58, which may be integral with one of the angle-pieces 8 or separate therefrom. .l/Vhen the instrument is not in use or is to be transported, the clampingscrew 56 is turned down, thereby bringing the upper enlargement 5'7 against the blambing-lever and throwing the inner end of the clamping-lever upwardly against the head This operation lifts the entire coil and clamps the conical heads thereof between the horizontal portion of the plate50 and the clamping lever, thus relieving the suspension ribb n of all strain. A movement of the screw in the opposite direction will obviously release the coil and allow it to hang free. Preferably the lever 53 will be so mounted that there will be sufficient friction at the fulcrum-point to hold said lever in any adjusted position, l use this construction because the suspension ribbon 17 isnecessarily very delicate, and where the lever is thus maintained in any adjusted position by friction it Will 0111 be moved for releasing or clamping the coi by the positive action of the clamping-screw 56.

6O designates leveling-screws by which the base or table 5 may be leveled. It is essential that these screws work through the base without any backlash or side shake, and

in order to provide a simple and inexpensive way of taking up any lost motion I screw said screws directly through the wood of the base 5 and then through friction-strips 61, which areseparated slightly from the base 5, as seen best in Figs. 1 and 6 and 14. A screw 62 passes through each friction member 61 and into the base 5, and by tightening each screw 62 more or less all lost motion in the corresponding leveling-screw may be entirely taken up and said screw made to operate smoothly and evenly and with any desired degree of friction.

The current is-talren into the instrument through a binding-post be, which is connected by a wire 55 with another bindingpost 56, the screw of the latter being cannected either to-the magnet or to one of the angleepieces 8. The current therefore passes to bindingpost 55 and to the magnet and from the latter to the suspension rod and suspension-ribbon l7 and to the coil 12 and from the latter to the binding post 30, as above described.

it will be understood that various changes in the construction and arrangement of the parts may be made without departing from the invention.

. Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is'

1. in a galvanometer, an inverted horseshoe-magnet, stilts or struts of non-magnetic material on which said magnet is supported, and a coilsuspended between the poles of the magnet to swing about a vertical axis.

2. in a galvanometer, a base or table, stilts of non-magnetic material rising therefrom, a horseshoe-ma net with parallel pole-pieces resting on said stilts, and a vertical coil suspended between said parallel pole-pieces.

3. in a galvanometer, a base, stilts of nonmagnetic material rising therefrom, horseshoe-magnet resting on said stilts, a coil sus pended between the poles of said ma net,

and transparent plates resting against the magnet and forming with the magnet an inclosing case for the coil.

at. in a galvanometer, a base, non-mag netic stilts rising therefrom, a horseshoemagnet arranged with its pole-pieces resting on said stilts, a coil suspended between said pole-pieces, and supports secured to the base and the sides of the magnet for holding the netic stilts rising therefrom, a horseshoepole-pieces, channel-shaped supports rigid,

with the base and embracmg the sides of the magnet and holding the latter in. position; and transparent plates overlying the magnet and clamped thereto by the channel-shaped rising therefrom, a magnet sustained by said supports.

7. In a galvanometer, a base, channelshaped supports rising from the base, an inverted horseshoe-magnet between said su 3 bracket, a rod passing through the slot of ports and sustained thereby, and asuspen ed coil in the field of the magnet.

8. In a galvanometer, a base, supports ris-T ing therefrom, an inverted horseshoe-magnet between said supports and sustained thereby, a non magnetic distance-piece between the magnet and base, and a coil suspended in the field of the magnet. 1

9. In a 'galvanometer, a base, channelshaped supports rising-therefrom, an inverted horseshoe-magnet between said supports and sustained thereby, and transparent platesoverlying the .magnet and clamped thereto by the channel-shaped supports.

10. In a galvanometer, a base supports rising therefrom, a magnet held iln osition by said supports, a suspended coil etween the pole-pieces of the magnet, brackets secured to said supports, and a reading device adjustably mounted on said brackets.

11. In a galvanometer, a base, supports rising therefrom, a magnet held in position between said supports, a suspended coil between the pole-pieces of the magnet, brackets sustained by the supports, and a reading device adjustably mounted on the brackets for movement transversely oil the magnet.

12. In a galvanometer, a base, supports rising therefrom, a magnet between said sup ports and held in position thereby, a coil suspended between the pole-pieces of the mag net, brackets extendingirom the supports, a

supporting-rod adjustably clamped to each.

bracket, and plates carryinga scale and a fiducial mark respectively, sustained said supporting-rods.

13. In a galvanometer a rising therefrom, a ma base, supports l be erases field of the magnet, brackets carried by the supports, a coil suspended in the field of the magnet, brackets carried by the supports, a slotted clamping-screw carried by each each clamping-screw,land plates carrying a scale and fiducial mark respectively sustained by said rods.

15. In a galvanometer, a pair of supports, a magnet sustained thereby, a bracket carried b each support, a horizontal rod adjustably c amped to each bracket, and plates carrying a scale and fiducial mark res ectively,

. pivotally connected to the rods at t eir ends.

tween said supports and sustained thereby, a.

coilsuspende between'the pole-pieces of the magnet, a protecting-shell inclosmg the coil, an means to immovably clamp said shell in inoperative position.

18. In a alvanometer, a base, a magnet supported t ereby, a coil operated by the magnet, leveling screws screw-threaded through the base, and friction members separate from the base and through which the leveling-screws pass, said friction members being adjustable with relation to the base,

to take up lost motion.

in testirn-on whereof I have signed my to this specification in the presence oi two subsez' sses.

' WYNN 

